Methods and compositions for treatment of lesioned sites of body vessels

ABSTRACT

Methods and compositions for inducing apoptosis of cells, such as macrophages, at a lesioned site of a body vessel are disclosed herein. Nitric oxide can be directly or indirectly delivered to a treatment site to increase macrophage apoptosis. Delivery can include site specific delivery of nitric oxide gas, nitric oxide in aqueous solution or a substance(s) which releases nitric oxide or causes nitric oxide to be generated from an endogenous source. Delivery can be achieved by a delivery system such as a catheter assembly, stent or other suitable device.

CROSS-REFERENCE TO RELATED APPLICATION

The application is a divisional of co-pending U.S. patent applicationSer. No. 11/404,233, filed Apr. 14, 2006 and incorporated herein byreference.

FIELD OF INVENTION

Methods and compositions for treating lesioned sites of atheroscleroticphysiological vessels using nitric oxide sources.

BACKGROUND OF INVENTION

“Arteriosclerosis” refers to the thickening and hardening of arteries.“Atherosclerosis” is a type of arteriosclerosis in which cells includingsmooth muscle cells and macrophages, fatty substances, cholesterol,cellular waste product, calcium and fibrin build up in the inner liningof a body vessel. If unstable or prone to rupture, the resultantbuild-up is commonly referred to as vulnerable plaque. It is generallybelieved that atherosclerosis begins with damage to the inner arterialwall resulting in a lesion. At the damaged site, substances such aslipids, platelets, cholesterol, cellular waste products and calciumdeposit in the vascular tissue may accumulate, leading to plaqueprogression and potentially the formation of vulnerable plaque. In turn,these substances lead to recruitment of cells involved in theinflammatory cascade of the immune system, such as macrophages, whichmay release substances leading to plaque destabilization.

Artherosclerotic lesions are characterized by a high content ofmacrophages which contribute to atherosclerosis by, for example,releasing free radicals, synthesizing bioreactive lipids, synthesizingcomplement components, synthesizing coagulation cascade components,secreting proteases and protease inhibitors, secreting cytokines andchemokines and phagocytosis of apoptic cells.

“Apoptosis” is the disintegration of cells into membrane-bound particlesthat are then eliminated by phagocytosis or by shedding. Researchstudies suggest that nitric oxide induces macrophage cell apoptosis. Forexample, a recent study has shown that the oral administration ofL-arginine, a substrate which releases nitric oxide, results inincreased apoptosis of macrophage cells (Wang et al., 1999. Circulation99; 1236-1241). Thus, macrophage apoptosis at lesioned sites of a bodyvessel is therefore desirable.

SUMMARY OF INVENTION

In accordance with embodiments of the present invention, nitric oxidecan be directly or indirectly delivered to a treatment site or region ofa body vessel to increase macrophage apoptosis. Delivery can includesite specific delivery of nitric oxide gas, nitric oxide in aqueoussolution or a substance(s) which releases nitric oxide or causes nitricoxide to be generated from an endogenous source, hereinaftercollectively referred to as “nitric oxide sources.” Delivery can beachieved by a delivery system such as a catheter assembly, stent orother suitable device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a cross-sectional view of a diseased blood vessel.

FIG. 2 illustrates a cross-sectional view of the blood vessel of FIG. 1and a first embodiment of a catheter assembly to deliver a nitric oxidesource to a blood vessel.

FIG. 3 illustrates a cross-sectional view of the blood vessel of FIG. 1and a second embodiment of a catheter assembly to deliver a nitric oxidesource to a blood vessel.

FIG. 4 illustrates a cross-sectional view of the blood vessel of FIG. 1and a third embodiment of a catheter assembly to deliver a nitric oxidesource to a blood vessel.

FIG. 5 illustrates an embodiment of a stent which may be used to delivera nitric oxide source.

DETAILED DESCRIPTION

Methods and compositions for inducing apoptosis of macrophage cells at alesioned site of a body vessel, such as a blood vessel, using nitricoxide sources are disclosed herein. It is to be understood thatreference to a lesioned site of a blood vessel is intended to includethe treatment of one or more lesioned sites, as well as treatment of oneor more regions, treatment sites, or injury sites of a blood vessel.Thus, the use of such terms may be referred to interchangeably hereinand are intended to be included within the scope of the presentinvention.

FIG. 1 illustrates an occluded blood vessel 100 with plaque build-up110. The injury site 110 can result in the increase of macrophage cellswhich accumulate modified low-density lipoprotein (LDL) and turn intofoam cells. Macrophage and foam cells secrete growth factors, cytokinesand other inflammatory mediators which influence the growth anddevelopment of other cell types within the atherosclerotic lesion, andthe recruitment of monocytes to the lesion. Macrophage-derived foamcells release lipids into the intima (inner layer) of the blood vesselresulting in increased plaque build-up 110. In addition, macrophagereleased growth factors cause proliferation of smooth muscle cells andthe plaque becomes fibrotic.

Methods for Inducing Macrophage Apoptosis

An excess amount of nitric oxide in macrophage cells can result inincreased macrophage apoptosis. Under normal conditions, macrophagecells produce nitric oxide to regulate various biological functions. Anoverproduction of nitric oxide, however, may be toxic to macrophagecells resulting in apoptosis. In accordance with the present invention,nitric oxide can be directly or indirectly delivered to a treatment site110 to increase macrophage apoptosis. Delivery can include site specificdelivery of nitric oxide gas, nitric oxide in aqueous solution or asubstance(s) which releases nitric oxide or causes nitric oxide to begenerated from an endogenous source, or substances that increase theamount of nitric oxide produced endogenously. Delivery can be achievedby a delivery system such as a catheter assembly, stent or othersuitable device.

Compositions

In some embodiments, nitric oxide gas can be directly delivered to alesioned site for treatment thereof. In some embodiments, nitric oxidegas can be diluted with a physiologically acceptable carrier gas fordelivery to a lesioned site thereof. Representative examples ofphysiologically acceptable carrier gases include, but are not limitedto, carbon dioxide, nitrogen, argon, helium, and perfluoro gases such asperfluoropentane or perfluoropropane. For example, small amounts ofnitric oxide may be mixed into perfluoropropane before introduction intoa vessel.

In some embodiments, nitric oxide gas can be mixed with a solvent (otherthan aqueous solutions such as saline or physiological buffers) which isphysiologically suitable for injection for delivery to a lesioned sitethereof. Such solvents include, but are not limited to, ethanol,dimethylsulfoxide, n-methylpyrrolidone, benzyl alcohol, benzylbenzoateand ethyl acetate. The solvent phase containing nitric oxide gas may bemixed with or emulsified into an aqueous solution such as saline.Alternatively, the nitric oxide may be mixed with one or more of acontrast agent, including, but not limited to, Omnipaque®, Imagopaque®,Optiray®, or Iopamido®.

In some embodiments, nitric oxide gas can be mixed with aqueoussolutions to create an aqueous solution for delivery to a lesioned sitethereof. The solution may be partially saturated, saturated orsuper-saturated. A “saturated solution” is one in which a solvent hasdissolved all of a solute possible at a given temperature. A“super-saturated solution” is one in which a solvent holds more solutethan it normally holds at a given temperature as it is cooling down. Asuper-saturated solution may be stabilized by addition of surfactantssuch as PVA (poly vinyl alcohol), PVP (poly vinyl pyrrolidone), lipids,including phospholipids, amphiphilic polymers such as polyethyleneglycol-polylactide (PEG-PLA) and ionic surfactants such as sodiumdodecyl sulfate (SDS). Although nitric oxide has limited solubility inwater (2-3 mM), it is believed that even a small or smaller quantity(e.g., less than about 2-3 mM) in solution delivered to a lesioned sitecan have beneficial effects.

In any of the above-described embodiments, the nitric oxide gas ornitric oxide gas solution may be encapsulated or formulated within acarrier for sustained release thereof.

Carriers can include, but are not limited to, an implantable medicaldevice, microspheres, nanoparticles, a gel or gel depot, a hydrogel orhydrogel depot, or a polymer or polymer depot for delivery and sustainedrelease thereof. Carriers and methods of formulating substance-loadedcarriers are known by those skilled in the art, an example of which canbe found in U.S. Pat. No. 6,656,506 to Wu et al., incorporated byreference herein.

In some embodiments, L-arginine or polypeptides of L-arginine can beencapsulated or formulated within a carrier such as, for example, animplantable medical device, microspheres, nanoparticles, a gel or geldepot, a hydrogel or hydrogel depot, or a polymer or polymer depot fordelivery and sustained release thereof. In the body of a mammal, nitricoxide is formed by the action of an endogenous enzyme, nitric oxidesynthase (NOS), on L-arginine resulting in the production of nitricoxide and citrulline. Nitric oxide synthases includes endothelial nitricoxide synthase (eNOS, NOS I), inducible nitric oxide synthase (iNOS, NOSII) and neuronal nitric oxide synthase (nNOS, NOS III). iNOS isexpressed in macrophages in response to various cytokines and microbialproducts. Once delivered to the treatment site, the L-arginine orpolypeptides of L-arginine can diffuse from the carrier and provide moresubstrate by which iNOS can act upon to produce a greater population ofNO within the localized treatment site. Other compounds suitable forformulation and delivery include, but are not intended to be limited to,L-arginine, L-homoarginine, and N-hydroxy-L-arginine, including theirnitrosated and nitrosylated analogs (e.g., nitrosated L-arginine,nitrosylated L-arginine, nitrosated N-hydroxy-L-arginine, nitrosylatedN-hydroxy-L-arginine, nitrosated L-homoarginine and nitrosylatedL-homoarginine), precursors of L-arginine and/or physiologicallyacceptable salts thereof, including, for example, citrulline, ornithine,glutamine, lysine, polypeptides comprising at least one of these aminoacids, inhibitors of the enzyme arginase (e.g., N-hydroxy-L-arginine and2(S)-amino-6-boronohexanoic acid) and the substrates for nitric oxidesynthase, cytokines, adenosine, bradykinin, calreticulin, bisacodyl, andphenolphthalein. For example, L-arginine may be encapsulated innanoparticles of from between about 250 nm to about 300 nm in diameterby water-oil-water emulsification. In the emulsification process,L-arginine is dissolved in an aqueous solution, which is added to apolymer-solvent phase, for example polylactic glycolic acid (PLGA)dissolved in acetone. The aqueous phase containing the peptide isemulsified into the polymer phase by application of energy, for exampleby sonification. This emulsion is then added to an aqueous solutioncontaining a small amount of an emulsifying agent such as poly-vinylalcohol, and a water-oil-water emulsion is formed by addition of energy,for example by sonication. L-arginine loaded polymer particles areformed by removal of the acetone and may be lyophilized for storage.

In some embodiments, L-arginine and NOS can be encapsulated in anactivated-release carrier such as a microsphere, nanoparticle, and thelike. In some embodiments, the activated-release carrier can bepermeable to both water and nitric oxide gas. Upon delivery, water canserve as the activating mechanism to start the enzymatic reaction of NOSon L-arginine. Once the reaction starts, nitric oxide gas can diffuseout of the activated-release carrier.

In some embodiments, a nitric oxide donor (NO donor), i.e., a nitricoxide-containing compound, and a suitable reactant (or no reactant) canbe encapsulated in an activated-release carrier such as, for example, amicrosphere, nanoparticle and the like. There are generally three kindsof mechanisms in which NO donors release NO: (I) spontaneously throughthermal or photochemical self-decomposition; (II) chemical reactionswith acid, alkali, metal and thiol; and (III) metabolic activation by NOsynthases or oxidases. These NO donors may be mono-nitrosylated,poly-nitrosylated, mono-nitrosated and/or poly-nitrosated or acombination thereof at a variety of naturally susceptible orartificially provided binding sites for biologically active forms of NO.

In category I, for example, the NO donor can be the family of NONOates(diazeniumdiolates), which include, but are not limited to,O(2)-(2,4-Dinitrophenyl)1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K),N-FU/NONOate, S-nitrosocaptopril and Man-1-SNAP. In one example, JS-Kcan be attacked by the nucleophilic thiol group of glutathione resultingin the formation of a Meisenheimer complex. The NONOate moiety(4-carbethoxy-PIPERAZI/NO) then dissociates from the complex. Atphysiological conditions, the NONOate decomposes to release nitricoxide. Other examples include furoxanes.

In category II, for example, the NO donor can be a nitrite or nitratesuch as sodium nitrite. A suitable reactant can include an appropriatereducing agent, such as sodium iodide, dithiothreitol, mercaptoethanol,iron particles, zinc particles, magnesium particles, sodium sulfide,sodium dithionite or sodium metabisulfite. When combined, the reducingagent reduces the nitric oxide donor such that the nitric oxide moietydisassociates from the metal ion. In some embodiments, theactivated-release carrier can be permeable to both water and nitricoxide. Upon delivery, water can serve as an activator to start thereaction.

Other examples for NO donors are compounds comprising at least oneON—O—, ON—N— or ON—C— group. The compounds that include at least oneON—O—, ON—N— or ON—C— group are preferably ON—O—, ON—N— orON—C-polypeptides; ON—O, ON—N— or ON—C— amino acids (including naturaland synthetic amino acids and their stereoisomers and racemic mixtures);ON—O—, ON—N— or ON—C-sugars; ON—O—, ON—N— or ON—C— modified orunmodified oligonucleotides (comprising at least about 5 nucleotides,preferably from about 5 nucleotides to about 200 nucleotides); ON—O—,ON—N— or ON—C— straight or branched, saturated or unsaturated, aliphaticor aromatic, substituted or unsubstituted hydrocarbons; and ON—O—, ON—N—or ON—C-heterocyclic compounds. The term “polypeptide” as used hereinincludes proteins and polyamino acids that do not possess an ascertainedbiological function, and derivatives and mimics thereof

Another group of NO donors include nitrates that donate, transfer orrelease nitric oxide, such as compounds comprising at least one O₂N—O—,O₂N—N—, O₂N—S— or O₂N—C— group. Preferred among these compounds areO₂N—O—, O₂N—N—, O₂N—S— or O₂N—C— polypeptides; O₂N—O—, O₂N—N—, O₂N—S— orO₂N—C— amino acids (including natural and synthetic amino acids andtheir stereoisomers and racemic mixtures); O₂ N—O—, O₂N—N—, O₂N—S— orO₂N—C-sugars; O₂N—O—; O₂N—N—, O₂N—S— or O₂N—C— modified and unmodifiedoligonucleotides; O₂N—O—, O₂N—N—, O₂N—S— or O₂N—C— straight or branched,saturated or unsaturated, aliphatic or aromatic, substituted orunsubstituted hydrocarbons; and O₂N—O—, O₂N—N—, O₂N—S— or O₂N—C—heterocyclic compounds. Preferred examples of compounds comprising atleast one O₂N—O—, O₂N—N—, O₂N—S— or O₂N—C— group include isosorbidedinitrate, isosorbide mononitrate, clonitrate, erythrityltetranitrate,mannitol hexanitrate, nitroglycerin, pentaerythritoltetranitrate,pentrinitrol and propatylnitrate.

In some embodiments, a nitric oxide generator (NO generator), i.e.,nitric oxide-containing compound, and a suitable catalytic agent can beencapsulated in an activated-release carrier such as a microsphere ornanoparticle. Examples of NO generators include, but are not limited to,nitrosylated proteins with cysteine residues which allow fornitrosylation at the thiol group. Examples of catalytic agents include,but are not limited to, copper ion complexes which cleave NO moietiesfrom nitrosylated proteins. Other examples for NO donor substrates areS-nitrosothiols, which are compounds that include at least one —S—NOgroup. These compounds include S-nitroso-polypeptides; S-nitrosylatedamino acids (including natural and synthetic amino acids and theirstereoisomers and racemic mixtures and derivatives thereof);S-nitrosylated sugars; S-nitrosylated, modified and unmodified,oligonucleotides; straight or branched, saturated or unsaturated,aliphatic or aromatic, substituted or unsubstituted S-nitrosylatedhydrocarbons; and S-nitroso heterocyclic compounds. In some embodiments,the activated-release carrier can be permeable to both water and nitricoxide. Upon delivery, water can serve as an activator to start thereaction.

In some embodiments, a drug which inhibits the enzymes arginases I andII (arginase inhibitors) can be delivered to the lesioned site fortreatment thereof. Arginases I and II control the production of nitricoxide from L-arginine by NOS I, II and III within macrophage cells. Byinhibiting arginase I and II, more L-arginine will be available as asubstrate to produce nitric oxide gas. Examples of arginase inhibitorsinclude, but are not limited to, (S)-(2-Boronoethyl)-L-cysteine andN^(ω)-Hydroxy-nor-L-arginine. In some embodiments, substrates such asantisense oligonucleotides or small interfering RNA (siRNA) can beintroduced to macrophage cells at the lesioned site to reduce arginaseexpression.

The nitric oxide donors, generators, substrates or gas may beco-formulated with a variety of pharmaceutical excipients such aspharmaceutically acceptable organic or inorganic carrier substancessuitable for parenteral application which do not deleteriously reactwith the active compounds. Examples of pharmaceutically acceptablecarriers include, for example, water, salt solutions, alcohol, silicone,waxes, petroleum jelly, vegetable oils, polyethylene glycols, propyleneglycol, liposomes, sugars, gelatin, lactose, amylose, magnesiumstearate, talc, surfactants, silicic acid, viscous paraffin, perfumeoil, fatty acid monoglycerides and diglycerides, petroethral fatty acidesters, hydroxymethyl-cellulose, polyvinylpyrrolidone, and the like.

In addition, nitric oxide donors, generators or substrates may beformulated for sustained release into an implantable medical device,micro- or nanoparticles made from polymer or ceramic materials, a gel orhydrogel depot or a polymer depot.

Delivery Systems and Methods

A variety of delivery systems known in the art can be used to delivernitric oxide gas, nitric oxide solutions, or a substance(s) whichreleases nitric oxide or causes nitric oxide to be generated from anendogenous source, i.e., nitric oxide sources, to a treatment site. Thedelivery systems include, but are not intended to be limited to,regional, local and direct delivery systems and injection systems, inaddition to stent deployment systems, and the like.

FIG. 2 shows blood vessel 100 having catheter assembly 200 disposedtherein. Catheter assembly 200 includes proximal portion 220 and distalportion 210. Proximal portion 220 may be external to blood vessel 100and to the patient. Representatively, catheter assembly 200 may beinserted through a femoral artery and through, for example, a guidecatheter and with the aid of a guidewire to a location in thevasculature of a patient. That location may be, for example, a coronaryartery. FIG. 2 shows distal portion 210 of catheter assembly 200positioned proximal or upstream from treatment site 110.

In one embodiment, catheter assembly 200 includes primary cannula 240having a length that extends from proximal portion 220 (e.g., locatedexternal through a patient during a procedure) to connect with aproximal end or skirt of balloon 230. Primary cannula 240 has a lumentherethrough that includes inflation cannula 260 and delivery cannula250. Each of inflation cannula 260 and delivery cannula 250 extends fromproximal portion 220 of catheter assembly 200 to distal portion 210.Inflation cannula 260 has a distal end that terminates within balloon230. Delivery cannula 250 extends through balloon 230.

Catheter assembly 200 also includes guidewire cannula 270 extending, inthis embodiment, through balloon 230 through a distal end of catheterassembly 200. Guidewire cannula 270 has a lumen sized to accommodateguidewire 280. Catheter assembly 200 may be an over the wire (OTW)configuration where guidewire cannula 270 extends from a proximal end(external to a patient during a procedure) to a distal end of catheterassembly 200. Guidewire cannula 230 may also be used for delivery of asubstance such as a nitric oxide source when guidewire 280 is removedwith catheter assembly 200 in place. In such case, separate deliverycannula (delivery cannula 250) is unnecessary or a delivery cannula maybe used to deliver one substance while guidewire cannula 270 is used todelivery another substance.

In another embodiment, catheter assembly 200 is a rapid exchange (RX)type catheter assembly and only a portion of catheter assembly 200 (adistal portion including balloon 230) is advanced over guidewire 280. Inan RX type of catheter assembly, typically, the guidewire cannula/lumenextends from the distal end of the catheter to a proximal guidewire portspaced distally from the proximal end of the catheter assembly. Theproximal guidewire port is typically spaced a substantial distance fromthe proximal end of the catheter assembly. FIG. 2 shows an RX typecatheter assembly.

In one embodiment, catheter assembly 200 is introduced into blood vessel100 and balloon 230 is inflated (e.g., with a suitable liquid throughinflation cannula 260) to occlude the blood vessel. Following occlusion,a nitric oxide source is introduced through delivery cannula 250. Byintroducing the nitric oxide source, the nitric oxide source can absorbon the walls of the blood vessel at treatment site 110.

In an effort to improve the target area of nitric oxide sources to atreatment site, such as treatment site 110, the injury site may beisolated prior to delivery. FIG. 3 shows an embodiment of a catheterassembly having two balloons where one balloon is located proximal totreatment site 110 and a second balloon is located distal to treatmentsite 110. FIG. 3 shows catheter assembly 300 disposed within bloodvessel 100. Catheter assembly 300 includes distal portion 310 andproximal portion 320 (external to a patient). Catheter assembly 300 hasa tandem balloon configuration including proximal balloon 330 and distalballoon 335 aligned in series at a distal portion of the catheterassembly. Catheter assembly 300 also includes primary cannula 340 havinga length that extends from a proximal end of catheter assembly 300(e.g., located external to a patient during a procedure) to connect witha proximal end or skirt of balloon 330. Primary cannula 340 has a lumentherethrough that includes first inflation cannula 360 and secondinflation cannula 375. First inflation cannula 360 extends from aproximal end of catheter assembly 300 to a point within balloon 330.First inflation cannula 360 and second inflation cannula 375 have lumenstherethrough allowing balloon 330 and balloon 335 to be inflated,respectively. Thus, in this embodiment, balloon 330 is inflated throughan inflation lumen separate from the inflation lumen that inflatesballoon 335. First inflation cannula 360 has a lumen therethroughallowing fluid to be introduced in the balloon 330 to inflate theballoon. In this manner, balloon 330 and balloon 335 may be separatelyinflated. Each of first inflation cannula 360 and second inflationcannula 375 extends from, in one embodiment, the proximal portion 320 ofcatheter assembly 300 through a point within balloon 330 and balloon335, respectively.

Catheter assembly 300 also includes guidewire cannula 370 extending, inthis embodiment, through each of balloon 330 and balloon 335 through adistal end of catheter assembly. Guidewire cannula 370 has a lumentherethrough sized to accommodate a guidewire. No guidewire is shownwithin guidewire cannula 370. Catheter assembly 300 may be an over thewire (OTW) configuration or a rapid exchange (RX) type catheterassembly. FIG. 3 illustrates an RX type catheter assembly.

Catheter assembly 300 also includes delivery cannula 350. In thisembodiment, delivery cannula 350 extends from a proximal portion 320 ofcatheter assembly 300 through a location between balloon 330 and balloon335. Secondary cannula 365 extends between balloon 330 and balloon 335.A proximal portion or skirt of balloon 335 connects to a distal portion310 of secondary cannula 365. A distal end or skirt of balloon 330 isconnected to a proximal end of secondary cannula 365. Delivery cannula350 terminates at opening 390 through secondary cannula 365. In thismanner, a nitric oxide source may be introduced between balloon 330 andballoon 335 positioned adjacent to treatment site 110.

FIG. 3 shows balloon 330 and balloon 335 each inflated to occlude alumen of blood vessel 100 and isolate treatment site 110. In oneembodiment, each of balloon 330 and balloon 335 are inflated to a pointsufficient to occlude blood vessel 100 prior to the introduction of anitric oxide source. The nitric oxide source may then be introduced.

In the above embodiment, separate balloons having separate inflationlumens are described. It is appreciated, however, that a singleinflation lumen may be used to inflate each of balloon 330 and balloon335. Alternatively, in another embodiment, balloon 330 may be aguidewire balloon configuration such as a PERCUSURG™ catheter assemblywhere catheter assembly 300 including only balloon 330 is inserted overa guidewire including balloon 335.

FIG. 4 shows another embodiment of a catheter assembly. Catheterassembly 400, in this embodiment, includes a porous balloon throughwhich a substance, such as a nitric oxide source, may be introduced.FIG. 4 shows catheter assembly 400 disposed within blood vessel 100.Catheter assembly 400 has a porous balloon configuration positioned attreatment site 110. Catheter assembly 400 includes primary cannula 440having a length that extends from a proximal portion 420 of catheterassembly 400 (e.g., located external to a patient during a procedure) toconnect with a proximal end or skirt of balloon 430 at distal portion410. Primary cannula 440 has a lumen therethrough that includesinflation cannula 460. Inflation cannula 460 extends from a proximal endof catheter assembly 400 to a point within balloon 430. Inflationcannula 460 has a lumen therethrough allowing balloon 430 to be inflatedthrough inflation cannula 460.

Catheter assembly 400 also includes guidewire cannula 470 extending, inthis embodiment, through balloon 430. Guidewire cannula 470 has a lumentherethrough sized to accommodate a guidewire. No guidewire is shownwithin guidewire cannula 470. Catheter assembly 400 may be anover-the-wire (OTW) configuration or rapid exchange (RX) type catheterassembly. FIG. 4 illustrates an OTW type catheter assembly.

Catheter assembly 400 also includes delivery cannula 450. In thisembodiment, delivery cannula 450 extends from a proximal end of catheterassembly 400 to proximal end or skirt of balloon 430. Balloon 430 is adouble layer balloon. Balloon 430 includes inner layer 425 that is anon-porous material, such as Pebax®, Nylon or polyethylene terephthalate(PET). Balloon 430 also includes outer layer 435. Outer layer 435 is aporous material, such as extended polytetrafluoroethylene (ePTFE). Inone embodiment, delivery cannula 450 is connected between inner layer425 and outer layer 435 so that a nitric oxide source can be introducedbetween the layers and permeate through pores 490 in balloon 430 into alumen of blood vessel 100.

As illustrated in FIG. 4, in one embodiment, catheter assembly isinserted into blood vessel 100 so that balloon 430 is aligned withtreatment site 110. Following alignment of balloon 430 of catheterassembly 400, balloon 430 may be inflated by introducing an inflationmedium (e.g., liquid through inflation cannula 460). In one embodiment,balloon 430 is only partially inflated or has an inflated diameter lessthan an inner diameter of blood vessel 100 at treatment site 110. Inthis manner, balloon 430 does not contact or only minimally contacts theblood vessel wall. A suitable expanded diameter of balloon 430 is on theorder of 2.0 mm to 5.0 mm for coronary vessels. It is appreciated thatthe expanded diameter may be different for peripheral vasculature.Following the expansion of balloon 430, a substance, such as nitricoxide source, is introduced into delivery cannula 450. The source flowsthrough delivery cannula 450 into a volume between inner layer 425 andouter layer 435 of balloon 430. At a relatively low pressure (e.g., onthe order of from about two to about four atmospheres (atm)), the nitricoxide source then permeate through the porous of outer layer 430 intoblood vessel 100.

In any of the above-described embodiments, the nitric oxide source maybe delivered to a treatment site through a delivery cannula. In someapplications, the delivery cannula may be pre-loaded at the proximal endwith a nitric oxide source, which may be a nitric oxide gas, a nitricoxide gas solution (aqueous or non-aqueous), an arginase inhibitor, or acarrier loaded with (a) L-arginine and optionally nitric oxide synthase,(b) a nitric oxide donor and suitable reactant or (c) a nitric oxidegenerator and suitable catalyst.

In some embodiments, the delivery system can be an implantable medicaldevice deployment system such as a stent deployment system.Representative examples of implantable medical devices include, but arenot limited to, self-expandable stents, balloon-expandable stents,micro-depot or micro-channel stents and grafts. FIG. 5 illustrates anembodiment of a stent. Stent 500 is generally tubular and includes alumen 510 with an abluminal surface 520 and a luminal surface 530. Stent500 can include a plurality of struts 540 connected by linking struts550 with interstitial spaces 560 located therebetween. The plurality ofstruts 540 can be configured in an annular fashion in discrete “rows”such that they form a series of “rings” throughout the body of stent500. Thus, stent 500 can include proximal ring 570, distal ring 580 andat least one central ring 590. Stent 500 can be metal, polymeric or anyother suitable biocompatible material.

In some embodiments, a stent may be fabricated from a biocompatiblemetal or metal alloy. Representative examples include, but are notlimited to, stainless steel (316L or 300), MP35N, MP2ON, Nitinol,Egiloy, tantalum, tantalum alloy, cobalt-chromium alloy, nickel-titaniumalloy, platinum, iridium, platinum-iridium alloy, gold, magnesium orcombinations thereof. MP35N and MP2ON are trade names for alloys ofcobalt, nickel, chromium and molybdenum available from Standard PressSteel Co., Jenkintown, Pa. MP35N consists of 35 percent (%), cobalt, 35%nickel, 20% chromium and 10% molybdenum. MP2ON consists of 50% cobalt,20% nickel, 20% chromium and 10% molybdenum.

In some embodiments, the stent can be coated with a biocompatiblecoating which includes a nitric oxide source. The nitric oxide sourcemay or may not be encapsulated in a sustained-release carrier or anactivated-release carrier such as those described previously.Representative examples of polymers that may be used to manufacture orcoat a stent, include but are not limited to, poly(N-acetylglucosamine)(Chitin), Chitosan, poly(hydroxyvalerate), poly(lactide-co-glycolide),poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate),polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide),poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic),poly(caprolactone), poly(trimethylene carbonate), polyester amide,poly(glycolic acid-co-trimethylene carbonate), co-poly(ether-esters)(e.g. PEO/PLA), polyphosphazenes, biomolecules (such as fibrin,fibrinogen, cellulose, starch, collagen and hyaluronic acid),polyurethanes, silicones, polyesters, polyolefins, polyisobutylene andethylene-alphaolefin copolymers, acrylic polymers and copolymers otherthan polyacrylates, vinyl halide polymers and copolymers (such aspolyvinyl chloride), polyvinyl ethers (such as polyvinyl methyl ether),polyvinylidene halides (such as polyvinylidene chloride),polyacrylonitrile, polyvinyl ketones, polyvinyl aromatics (such aspolystyrene), polyvinyl esters (such as polyvinyl acetate),acrylonitrile styrene copolymers, ABS resins, polyamides (such as Nylon66 and polycaprolactam), polycarbonates, polyoxymethylenes, polyimides,polyethers, polyurethanes, rayon, rayon-tracetate, cellulose, celluloseacetate, cellulose butyrate, cellulose acetate butyrate, cellophane,cellulose nitrate, cellulose propionate, cellulose ethers, andcarboxymethyl cellulose. Another type of polymer based on poly(lacticacid) that can be used includes graft copolymers, and block copolymers,such as AB block-copolymers (“diblock-copolymers”) or ABAblock-copolymers (“triblock-copolymers”), or mixtures thereof.

Additional representative examples of polymers that may be especiallywell suited for use in manufacturing or coating stents include ethylenevinyl alcohol copolymer (e.g., EVOH or EVAL), poly(butyl methacrylate),poly(vinylidene fluoride-co-hexfluorapropene (e.g., SOLEF 21708,available from Solvay Solexis PVDF, Thorofare, N.J.), polyvinylidenefluoride (e.g., KYNAR, available from ATOFINA Chemicals, Philadelphia,Pa.), ethylene-vinyl acetate copolymers and polyethylene glycol.

In some applications, a polymer coating comprising at least one layerincluding a nitric oxide source can be applied to a surface of a stentfor controlled release of the nitric oxide source. For example, acoating can include one or a combination of the following types oflayers: (a) a treatment agent layer, which may include a polymer and atreatment agent, or alternatively, a polymer-free treatment agent; (b)an optional primer layer, which may improve adhesion of subsequentlayers on the stent or on a previously formed layer; (c) an optionaltopcoat layer, which may serve to control the rate of release of thetreatment agent; and (d) an optional biocompatible finishing layer,which may improve the biocompatibility of the coating. The treatmentagent can be a nitric oxide source.

In some embodiments, the coating can be partially or completely appliedto an abluminal surface or a luminal surface of the stent. The coatingcan be applied by methods known by those skilled in the art, including,but not limited to, dipping, spraying, pouring, brushing, spin-coating,roller coating, meniscus coating, powder coating, drop-on-demandcoating, sputtering, gas-phase polymerization, solvent inversion or anycombination thereof. Coating techniques are known by those skilled inthe art.

In some embodiments, a stent may be fabricated from a bioerodable orbiodegradable polymer to form a polymeric stent. Manufacturing processesfor forming a polymeric stent include, but are not limited to, casting,molding or combinations thereof. Casting involves pouring a liquidpolymeric composition into a mold. Molding processes include, but arenot limited to, compression molding, extrusion molding, injectionmolding and foam molding. In compressing molding, solid polymericmaterials are added to a mold and pressure and heat are applied untilthe polymeric material conforms to the mold. In extrusion molding, solidpolymeric materials are added to a continuous melt that is forcedthrough a die and cooled to a solid form. In injection molding, solidpolymeric materials are added to a heated cylinder, softened and forcedinto a mold under pressure to create a solid form. In foam molding,blowing agents are used to expand and mold solid polymeric materialsinto a desired form, and the solid polymeric materials can be expandedto a volume in a range from about 2 to 50 times their original volume.In the above-described molding embodiments, the solid form may requireadditional processing to obtain the final product in a desired form.

In some embodiments, a nitric oxide source may be directly incorporatedinto the body of a polymeric stent during the manufacturing process. Forexample, a nitric oxide source may be combined with a polymer matrix andsubsequently subjected to any of the above-described manufacturingprocess for formation thereof. In this aspect, the nitric oxide sourcemay be released in a controlled manner as the polymeric stent naturallydegrades over time.

From the foregoing detailed description, it will be evident that thereare a number of changes, adaptations and modifications of the presentinvention which come within the province of those skilled in the part.The scope of the invention includes any combination of the elements fromthe different species and embodiments disclosed herein, as well assubassemblies, assemblies and methods thereof. However, it is intendedthat all such variations not departing from the spirit of the inventionbe considered as within the scope thereof.

1. A composition comprising: an amount of an agent suitable for deliveryinto a body vessel wherein the agent directly or indirectly induces cellapoptosis at a lesioned site.
 2. The composition of claim 1, wherein theagent is encapsulated within a carrier.
 3. The composition of claim 2,wherein the carrier is selected from the group consisting of animplantable medical device, a microsphere, a nanoparticle, a gel, a geldepot, a hydrogel, a hydrogel depot, a polymer and a polymer depot. 4.The composition of claim 1, wherein the agent is a nitric oxide source.5. The composition of claim 4, wherein the nitric oxide source isselected from the group consisting of a nitric oxide gas, a nitric oxidesolution or a nitric oxide derivative solution.
 6. The composition ofclaim 1, wherein the agent is an amino acid.
 7. The composition of claim6, wherein the amino acid is L-arginine or a polypeptide of L-arginine.8. The composition of claim 1, wherein the agent is adapted to inhibitarginase I or arginase II.
 9. The composition of claim 1, wherein theagent further comprises: a first agent; and a second agent.
 10. Thecomposition of claim 9, wherein the first agent is selected from thegroup consisting of a nitric oxide-containing compound and L-arginine.11. The composition of claim 10, wherein the second agent is selectedfrom the group consisting of a compound suitable for reacting with thenitric oxide-containing compound and nitric oxide synthase.
 12. Thecomposition of claim 9, wherein the first agent and the second agent areencapsulated within a carrier.
 13. The composition of claim 9, whereinthe first agent or the second agent is encapsulated within a carrier.14. The composition of claim 12, wherein the carrier is selected fromthe group consisting of an implantable medical device, a microsphere, ananoparticle, a gel, a gel depot, a hydrogel, a hydrogel depot, apolymer and a polymer depot.
 15. The composition of claim 13, whereinthe carrier is selected from the group consisting of an implantablemedical device, a microsphere, a nanoparticle, a gel, a gel depot, ahydrogel, a hydrogel depot, a polymer and a polymer depot.
 16. Thecomposition of claim 1, wherein the cell is at least one macrophagecell.
 17. A treatment kit comprising: a nitric oxide source; and adelivery device.
 18. The kit of claim 17, wherein the nitric oxidesource is encapsulated in a carrier.
 19. The kit of claim 17, whereinthe nitric oxide source is selected from the group consisting of anitric oxide gas, a nitric oxide solution, a nitric oxide compositionand L-arginine.
 20. The kit of claim 19, wherein the nitric oxidecomposition includes a first agent and a second agent.
 21. The kit ofclaim 20, wherein the first agent is selected from the group consistingof a nitric oxide-containing compound and L-arginine.
 22. The kit ofclaim 20, wherein the second agent is selected from the group consistingof a compound suitable for reacting with the nitric oxide-containingcompound and nitric oxide synthase
 23. The kit of claim 20, wherein thefirst agent and the second agent are encapsulated within a carrier. 24.The kit of claim 20, wherein the first agent or the second agent isencapsulated within a carrier.
 25. The kit of claim 23, wherein thecarrier is selected from the group consisting of an implantable medicaldevice, microspheres, nanoparticles, a gel, a gel depot, a hydrogel, ahydrogel depot, a polymer and a polymer depot.
 26. The kit of claim 24,wherein the carrier is selected from the group consisting of animplantable medical device, microspheres, nanoparticles, a gel, a geldepot, a hydrogel, a hydrogel depot, a polymer and a polymer depot. 27.The kit of claim 17, wherein the delivery device is a catheter assembly.